JPS58216278A - Picture formation device - Google Patents

Abstract

PURPOSE:To easily and surely collect all remaining toner to a developing section, by forming a toner deposit on an electric charge holding member with a remaining toner cleaning blade and receiving toner dropping from the deposit with a preventing member. CONSTITUTION:A cleaning blade 18, which is selectively contacted with a photosensitive drum 1 and collects remainng toner, and a plate-like drop preventing member 9, which receives dropping toner, are installed to the down stream side of a transferring section equipped with a transferring and stripping corona electrostatic chargers 12 and 13 and upstream side of an electrostatic charger 2. The blade 18 is contacted with the drum 1 at the position of the solid line at the time of copying by means of a driving means 20 and once retracted to the position of a virtual line at an appropriate time before starting the next copying. When the blade 18 is retracted, it seuds a toner deposit to a magnetic roll 8. The drop preventing member 19 is a sheet of polyester, metal, etc., and installed closely to the blade 18 at the upstream side. The member 19 is contacted with or brought closely to the drum 1 and held by a holding member 21 at a position extended to the blade side.

Description

[Detailed description of the invention]

This invention is twice! l1IliIf0)notJ endless 11
1. An electrostatic latent image is formed on the load holding member, and this electrostatic latent image is converted into a toner image by a developing device using a dry developer.
2. This relates to an image forming apparatus which generates an N image and transfers this toner image to a recording sheet.2. . Such image formation! As a 4+1 nail, for example, an electrostatic latent image corresponding to a gon image formed on a rotating Shigeko photosensitive 1.lambda. is toner-equalized by a developing device using a dry type developer, and this σ) toner image is created. A device is known that transfers the image data onto copy paper and makes a copy. In such electrophotographic devices, after the toner image is transferred to the copy paper, the photosensitive drum is transferred to the photosensitive drum prior to the formation of the latent image. It is necessary to clean the remaining l/ner that has not been transferred to the copy paper and remove it. As a conventional method, methods using a fur brush, a method using a blade, a method using a magnetic brush, etc. have been proposed. On the other hand, like this dry IJJ
f? In an electrophotographic device that uses toner to develop an electrostatic latent image formed on a photosensitive drum by a developing device using a developer, after the toner image is transferred to copy paper, the remaining toner on the photosensitive drum is collected by the developing device and recycled. It is preferred to use However, in the above-mentioned cleaning device using a fur brush, the residual toner removed by the fur brush is generally captured by a filter and discarded by an air flow generated by an air suction mechanism, so it cannot be collected in the developing device, and the Since a suction mechanism and filter are required, acceptance inspection is complicated and the electrophotographic device is large.In contrast, a cleaning device using a blade is not suitable for cleaning with elastic materials such as urethane. Since the blade, which is made up of a member, is brought into contact with the photosensitive drum for cleaning, the structure can be made simple and compact, and
Since the residual toner on the photosensitive drum is collected by the blade, it can be reused by transferring it to the developing device. However, in a conventional electronic page device using this type of cleaning device, the residual toner collected by the blade collects in the toner container when it is exposed to light and falls off from the plum. The toner can be manually collected into the developing device periodically, or the toner stored in the toner container can be automatically collected into the developing device by using a separate toner conveying means having a flexible screw or the like. In the former case, maintenance becomes troublesome, and in the latter case, the equipment becomes expensive and
There is a problem that the configuration of the toner conveying means becomes complicated. In addition, the cleaning device using a magnetic brush may be used in combination with the developing device H itself (σ), and in this case, the cleaned toner can be directly taken into the developing device, so other methods Remove the cleaned toner from the electrophotographic device, or 'f)
It has the advantage of not requiring regular maintenance to collect toner into the device or a complicated device to automatically return cleaned toner to the developing device, resulting in lower device costs and improved maintainability. It is extremely advantageous in this respect. but,
In this way, when the developing device is also used as a cleaning device, the developing device is usually placed between the latent image forming section and the toner image transfer section, so the toner image transferring section and the latent image forming section are Cleaning and development can be performed at the same time, like an electrophotographic device that has a dedicated cleaning device in between. Therefore, when making continuous copies, it is not necessary to use a photosensitive drum to make one copy. It is necessary to rotate the photosensitive drum at least twice, and it is also necessary to make the outer circumferential length of the photosensitive drum longer than the maximum length of copy paper. For this reason, when configuring an apparatus with the same copying speed, the process speed must be set faster than an apparatus with a dedicated cleaning device, and since the shape of the photosensitive drum cannot be made smaller, the entire apparatus becomes larger. There is a problem with it. FIG. 1 is a diagram showing the configuration of an example of an electrophotographic apparatus which is used as both a developing device and a cleaning device as described above. In FIG. 1, when a copying operation starts, the photosensitive drum rotates in the direction of the arrow and is uniformly charged by the corona charger 2. In FIG. The copy document is placed on the movable document table 8 and starts to move in the direction of the arrow, and the 1111 bright lamp 4 and the reflector 5
lfl light, fiber lens array 6"'C
A ll1I image is projected on II% light F 5 11-,
As a result, an electrostatic latent image corresponding to f@I is formed on the photosensitive drum 1. This static NY layer [9 is toner-developed by a magnetic brush roller 8 of a developing device 7 using a dry developer, and this toner m is previously transferred to a pickup roller 1 from a cassette 9.

[; and the copy month 1 sum being sent out by the feeding roller 11, and are transferred to the copy paper by the action of the transfer corona charger 19. This copy material is peeled off from the nC optical drum 1 by the action of the peeling corona charger 18 and then sent to the fixing roller 14.
The toner image is fixed on the discharge roller 15.
It is discharged to the beat tray 16. Copy paper - no.1・→-
- After the image transfer, a cleaning process is carried out to remove the residual particles remaining on the photosensitive drum 1+; 1. Continue to rotate the photosensitive drum 1 once. 1 Ru. First, the electric charge on the photosensitive drum 1 having the residual toner on its surface is eliminated by the equalization light emitted by the static eliminating lamp 17, and then the remaining toner is removed by the rubbing of the magnetic brush roller 8 of the developing device 7. 7 to collect. Thereafter, when the photosensitive drum 1 from which the residual toner has been removed rotates to the position of the corona charger 2, the next document is prepared and the next copying operation begins, so to speak. That is, in order to obtain continuous copies, the photosensitive drum 1 needs to rotate twice for each FP. Furthermore, in order to use the same developing device 7 for development and cleaning, the outer circumferential length of the photosensitive drum 1 needs to be longer than the maximum copy dimension. Such a constraint condition requires that the peripheral speed of the photosensitive drum 1 be increased in order to obtain the same number of copies per unit time when compared with an electrophotographic apparatus having a dedicated cleaner.
ji2, 12, 13, illumination lamp 4, developing device w7,
This places a large burden on the fixing roller 14 and the like. Also, if you want to create a small size copy, do you need a special cleaner? In an electrophotographic device that has a 3D printer, it is possible to increase the number of copies per unit time by changing the reciprocating range of the document table and scanning optical system to match the copy size. Even if the size is reduced, the number of copies per unit time cannot be increased.Furthermore, in devices equipped with a dedicated cleaner, the number of copies per unit time cannot be increased unless the return speed of the 161° stand and scanning optical system is increased. In the apparatus shown in Figure 1, it is not possible to increase the number of copies per unit time even if the return speed is increased. Is it possible to make the device as small as possible within the limits that allow related devices to be placed on the IN side of the drum? With the device shown in Figure 1, it is not possible to use a drum with a circumference of 1 below the maximum copy length. In addition, regarding the cleaning function, the current 4@ml
7 N! -Leaning properties are sufficient for dual use.#
In order to increase the T1 and I4, auxiliary improvements such as increasing the developing bias %1 and F[• during cleaning are required. Despite these numerous drawbacks, the reason why electrophotographic devices that function as both a developing device and a cleaning device has been put into practical use is because they do not require a dedicated cleaning device that is complicated and difficult to maintain. This is because it has the advantage that all of the removed toner can be reused. An object of the present invention is to eliminate the disadvantages of using the developing device as a cleaner without sacrificing the advantages thereof, and to easily and reliably collect residual toner on the load holding member into the developing device. Appropriately configured image forming apparatus (4F,
L is what I'm trying to do. In the present invention, a static latent image is formed on a rotatable endless load holding section H, and this electrostatic latent image is developed into a toner image by a developing device using a dry developer. In an image forming apparatus configured to transfer images onto a recording paper, a cleaning blade selectively contacts the charge retaining member to collect toner remaining on a box or a load holding member after the toner image is transferred onto the recording paper; , in the vicinity of the cleaning blade, touches or approaches the charge retention member on the upstream side with respect to the rotating direction of the charge retention member, and extends to the cleaning blade side to prevent lightning and load on the cleaning blade. Is the toner falling from the toner pool formed at the contact portion of the cleaning blade due to contact with the holding member? i'-9 Toner fall prevention [E component] Hold the cleaning blade to the toner reservoir formed by contact with the material, hold the cleaning blade, and remove the load. ηs apart from the holding member? l
It is characterized in that it is configured so that it is conveyed to the developing device by a rotating roller having a length of 4'4 and 17 times. Is the drawing below? The present invention will be explained in detail below. Fig. 2 is a diagram showing the configuration of the main parts of an example of a child photographic device according to the present invention, and the reference numerals shown in Fig. 1 are The same reference numerals represent the same functions 1. In the configuration shown in FIG. 2, the major difference from FIG. On the downstream side of the image transfer section, there is a corona charging gain of 2, 1 - current + 1
111, a cleaning blade 18 made of an elastic material such as urethane that selectively contacts the photosensitive drum 1 and collects residual toner; and a plate-shaped toner drop that reduces the amount of toner that falls from the toner pool collected by this blade 18. A prevention member 10 was provided! It is in. On the downstream side of the blade 18, it is preferable to install one #CC clamp (not shown) and a corona remover (not shown). The blade 18 is always in contact with the photosensitive drum 1 as shown by the solid line during the copying operation by the blade driving means 2°, and at any time after the completion of m@ formation for the preceding copy and before the start of latent image formation for the subsequent copy. At this point, it is configured to automatically retreat to the imaginary line position -2 and separate from the photosensitive drum 1, and then return to the solid line position and come into contact with the photosensitive drum 1. The toner fall prevention member 9 is preferably made of an elastic material such as a plastic sheet such as a polyester film or a metal thin plate such as stainless steel, and is brought into contact with the photosensitive drum 1 on the upstream side near the blade 18. Alternatively, the blade 18 may be brought close to the blade 18 and held by the holding member 2. 8A, B, and 0 are diagrams for regulating the operation of the blade 18, and the X mark in the figure indicates the rear end of the area of the photosensitive drum 1 that requires cleaning. 8A, when the blade 18 is brought into contact with the photosensitive drum 1, the residual toner on the photosensitive drum 1 is removed by the blade 18.
A toner pool 22 is formed at the tip of the blade. After cleaning the area to be cleaned, as shown in FIG. 8B, the toner pool 22 is removed from the photosensitive drum 1 by retracting the blade 18 from the virtual line position to the actual position IN. As a result, the photosensitive drum 1 remains on the photosensitive drum 1, is picked up by the rotation of the photosensitive drum 1 in the direction of the developing device, and is collected by the magnetic brush roller 8 into the developing device 7 as shown in FIG. . In FIG. 80, the blackened area shows the toner that had flowed onto the drum and formed a toner reservoir. The toner reservoir 22, which has been transported to the developing device 17 by the photosensitive drum, forms a thick layer and the blade 18
The toner is once scraped from the photosensitive drum by the toner, and there is an electrostatic charge between the toner and the photosensitive drum, which creates an attractive force.
Moreover, since the toner pool 22 also contains air particles generated when the blade 18 slides in the action 111, the adhesion force to the photosensitive drum 1 is extremely weak and can be easily removed. . Therefore, when collecting the toner pool 22 from the photosensitive drum 1 with the magnetic brush roller 8 of the fM latent image w1, there is an advantage that no additional improvement such as increasing the image bias bias pressure is required. It should be noted that there are no particular restrictions in principle regarding the developing device and dry developer applied to the present invention. A relatively wide space between the sleeve for transporting and holding the agent and the photoreceptor can be suitably applied without causing any additional problems. Further, the means for collecting the toner cleaned by the developing device is not limited to the contact of the magnetic brush roller 8 that holds the developer in a brush shape around the circumference as shown in FIG. This may be achieved by physical means. For example, a scraper is placed upstream of the developing device 7 with its tip touching or very close to the photosensitive drum 1, and the toner pool 22 collected by the scraper is placed in the toner hopper or developer of the developing device 7. It may be configured to be introduced. In FIG. 8A-0, due to the separation of the blade 18 from the photosensitive drum 1, most of the toner pool 22 collected by the cleaning blade 18 is transferred to the photosensitive drum 1+ and transported to the developing device @7. 11.4
11Ij <Some toner, especially those that agglomerate when being applied to the blade 18, have a force greater than the adhesion strength to the photosensitive drum 1 and the blade 18. Dropped out from 22. Conventional blade-type cleaning device (here, this one)
・Use the falling action of →- to collect the remaining toner to 1 Jl.
-Kon Juru J: 6-cost of toner that fell off because of the sea! - There were problems such as requiring a separate Fner container and requiring maintenance work. On the other hand, in this ψ embodiment, as shown in the enlarged diagram in Figure 4, the toner is brought into contact with or close to the photosensitive drum 1 on the upstream side near the blade 18, and extends toward the blade 18 side, causing toner to fall. Since the prevention member 19 is provided, the toner that has fallen from the toner reservoir 22 is collected by the triangular part formed by the toner filling prevention part 1 (formed by 1, the photosensitive drum 1, and the drum 1). In addition, the toner fall prevention member 19
The toner that has been stopped from being received is broken into fine powder again by the rotation of the photosensitive drum 1, adheres to the photosensitive drum 1, is collected by the scattering blade 18, forms a toner pool 22, and is removed from the photosensitive drum 18. When separated from the drum 1, the photosensitive drum 1 is conveyed to the developing device 7 and collected. In this way, the toner fall prevention member 9 has the function of preventing the toner collected by the cleaning blade 18 from falling, and the toner cloud that is generated when the blade 18 comes into contact with and leaves the photosensitive drum 9 is diffused to prevent electrophotography. This also has the effect of preventing contamination of the inside of the device. In the embodiment described above, the holding member 21 that holds the toner fall prevention member 19 may be arranged in a fixed manner, and the toner fall prevention member 19 can be moved in the direction in which it comes into contact with the photosensitive drum 1 in the same manner as the blade 8. It may be configured as follows. When configured to be movable, the blade 18 and the holding member 21
The blade 18 and the blade 18 may be movable independently of each other, and the blade 18 and -W'1 of the blade 18 itself or the member holding the blade may be used as the holding cover 21. It may be configured to be movable as a unit. The holding member 2 can be moved in this way.
(Jl) When the toner fall prevention member 19 is provided with sufficient flexibility, the toner fall prevention member 19 is prevented from overhanging the photosensitive drum 1 by the movement of the holding member 2'1.
The photosensitive drum 1 is always kept in contact with the photosensitive drum 1 so as not to damage the surface of the photosensitive drum 1 due to excessive pressure. In this way, unless the toner fall prevention member 19 is curvedly displaced in the direction of tlllf with respect to the photosensitive drum 1, the toner mass stopped by the toner fall prevention member 19 can be crushed in the tank frame. This makes it possible to easily make the film resistant to adhesion to the photosensitive drum. 6A, B, and 0 show eight examples in which the toner fall prevention member 19 is displaced one turn. Fifth
In Figure A, the holding member 21 is configured to be movable in the direction of the arrow independently of the blade 18, and by reciprocating the holding member 21, the toner fall prevention member 19 can be moved as shown by solid lines and virtual gauze. The toner drop prevention member] 9 is configured to pulverize the toner lumps stopped by the toner fall prevention member 9. The timing to move the holding member 21 is as follows:
Although it may be set arbitrarily, for example, if it is linked with the movement of the blade 18, the control circuit and movement mechanism can be greatly simplified. Figure 5B shows blade 1
8 and the toner fall prevention member 19 are held by a common holding member 2a, and this holding member 23 is movably supported around the axis 24'fr-, thereby displacing the blade 18 and the toner fall prevention member 9 integrally. This is how it was done. FIG. 5B shows a state in which the blade 18 is in contact with the photosensitive drum. When the holding member 28 rotates clockwise, the blade 18 separates from the photosensitive drum 1 and the toner fall prevention member 19 is displaced by one turn in the direction approaching the photosensitive drum 1, and the receiver acts to crush the stopped toner lumps and pulverize them. In addition, in order to more effectively pulverize the toner lumps that have been stopped by the toner drop prevention member 9 in Fig. 5C, the toner fall prevention member 19 is installed in the cypress 1N (not shown in Fig. 5B & T). The blade 18 (the part extending from the part that contacts the photosensitive drum 11j to the photosensitive drum 1
The raised soft part 4i4'B5 is placed on the surface facing the v&. The raised member 25 may be a raised fabric made by inserting rigid and delicate fibers, for example, acrylic fibers into the base fabric. The raised member 25 comes into contact with the photosensitive drum 1 in response to the swinging of the holding member 28, thereby acting to push the bristles into the toner mass and pulverize the toner. Note that this raised member 25 can also be used in the configuration shown in FIG. 6A. FIG. 6A-() is a timing chart showing an example of the operating state of each process element in the case of continuous copying in the military photographic apparatus shown in FIG. 2. In this example, 1 bright lamp 4. , currently @device? , corona w box for transfer, container 1fA and corona charging for peeling, container 18
The tipping device, the load removal device, and the ramp 17 are shown in FIG. 6, 0. During continuous copying operations as shown in D, IC, and F, the cleaning blade 18, corona charger, container 2, and movable document table or scanning optical system are activated during continuous copying operations as shown in FIGS. 6A, B, and F, respectively. The operating state is controlled in connection with successive copy operations as shown in G. The operation will be explained below with reference to FIGS. 2 and 3. When the copy operation starts at time TI & here, the 6th
All devices shown in Figures A-G are in operation. At time T2, as shown in FIG. 6G, the document table or the scanning optical system travels a predetermined distance, reverses from forward movement to backward movement, stops at time T5, and starts again at time T8. That is, it means that latent image formation ends at time T2, and latent image formation resumes at time T8. As shown in FIG. 6A, the cleaning plate 18 is once separated from the photosensitive drum 1 at a time when no latent image is formed, that is, at any time between times T2 and T8, and the residual toner collected by the blade 18 is removed. The pool 22 is conveyed by the rotation of the photosensitive drum 1 and collected in the developing device 7. To define more strictly the time range for once separating the blade 18 from the photosensitive drum 1, the portion of the photosensitive drum 1 that is applied to the trailing edge of the image to be formed first passes through the blade 18. This is the period from when the blade 18 reaches the blade 18, which corresponds to the leading edge of the next image to be formed. 1 distance from the photosensitive drum 1. Time T2 to T8 or time T shown in FIG.
fl~T7 are blade IIAFs set within the above conditions.
Two examples of 1111 hours are shown. Corona obi and container B have at least the same cleaning blade 18.
The toner pool 22 stirred by the corona charge 1
The blade 18 shown in FIG.
Corresponding to the separation time T2-T8 or T6-T7 +llI! As shown in Fig. 6B, at time T2~
T4 or time T6-T8 song, corona charger 2)) Set as a non-working axis. In this way, if the corona charger 2 is made inactive during the period when the toner pool 22 stirred up by the cleaning blade 18 passes through the corona charging portion kR2,
Since the toner reservoir 22 is not undesirably charged, it is possible to effectively prevent image quality deterioration and developer deterioration caused by the toner reservoir 22 being charged 1. In the control example shown in FIG.
When configured as shown in FIG. 5B and C,
If the blade 18 moves away from the photosensitive drum 1, the toner fall prevention member 19 will also inevitably undergo a curved displacement, as shown in FIG. 5A.
When the blade 18 and the toner fall prevention member 19 are held movably independently of each other as shown in FIG.
1 may be configured to move at any timing or in conjunction with the operation of any device such as the blade 18, the corona charger 2, or the original scanning device. Note that the present invention is applicable not only to the above-mentioned electrophotographic device, but also to an i
It can also be effectively applied to a device using a WI'flL recording member. As described above, in the present invention, the residual toner on the charge changing member is scraped off by contact with the cleaning blade. +(l') A toner pool is formed on the charge holding part H, and the toner falling from this toner pool is received by a toner fall prevention member and is again stuck on the charge holding part H. Toner sharpening blade 1
φ ("Electricity nor
Since it is conveyed to the developing device and collected by the rotation of the holding part, the simple structure allows for IN, ER holding, and
4:, 400) Martyr Wj) All of the ners into a latent image device? #
It's easy and child 1f actual performance this time Ill/I can do it. Therefore, maintenance work for the cleaning toner treatment is not required as in the conventional method.
As shown in Figure 2, by applying an elastic part to the container and selectively displacing it in the direction of contacting the load holding member, it is possible to effectively remove the toner lumps that have been stopped by the toner fall prevention member.
In addition, if a raised member is provided on the side of this toner fall prevention +l-W+I material facing the box cargo holding member as shown in FIG. It can be done more effectively. History number: Assemble the cleaning blade and toner fall prevention member as shown in Figure 5 B and C.
If you hold it together as shown in ! The configuration can be further simplified. Furthermore, in the present invention, since a cleaning device having a blade is provided, it has both the advantage of having a dedicated cleaning device and the advantage of being used as both an image device and a cleaning device.ii! Il image formation, the device can be realized.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the configuration of a conventional electrophotographic device, FIG. 2 is a diagram showing the configuration of essential parts of an example of the electrophotographic device according to the present invention, and FIGS. 8A, B, and C are the same. 4 is a partially enlarged diagram of FIG. 2, and FIG. 5 A, B, and C are configurations of essential parts of eight other examples of electrophotographic apparatuses according to the present invention. FIGS. 6A to 6G are timing charts showing an example of the operation of each part of the electrophotographic apparatus shown in FIG. 1... Photosensitive drum 2... Corona charger 8.
...Moving document table 4...Illumination lamp 5...Reflection-5 6...Fiber lens array 7...Developing device 8...Magnetic brush roller 9...Cassette 10...Pickup roller 11 ... Feeding roller 12 ... Corona charger for rolling] 8 ... ψIIIF C1 corona charger 14 ... Fixing roller 15 ... Ejection roller 16
...Copy tray 17...Lightning removal, lamp 18
...Cleaning blade 19...Toner fall prevention member 2 (1...Blade drive means 21, 28...Holding member 8B...Toner pool 2
4... Axis 2F+... Raised member. Figure 1 Figure 3 Figure 4 Figure 5 Figure 5 Figure 8

Claims (1)

[Scope of Claims] 1. An electrostatic latent image is formed on a rotatable endless charge holding member, and this electrostatic latent image is developed into a toner image by a developing device using a dry developer. In an image forming apparatus configured to transfer an image onto a recording paper, cleaning is performed to selectively contact the toner holding member to collect toner remaining on the toner holding member after the toner image is transferred to the recording paper. a charge retaining member of the cleaning blade, which is arranged in the vicinity of the cleaning blade, contacts or approaches the charge retaining member on the upstream side with respect to the rotating direction of the charge retaining member, and extends toward the cleaning blade; and a plate-shaped toner fall prevention member for receiving toner falling from a toner reservoir formed at the contact portion of the cleaning blade by contact with the cleaning blade, the toner drop prevention member being formed by the contact of the cleaning blade with the load holding member. Toner pool,
An image forming apparatus characterized in that the cleaning blade is separated from the charge holding member and is conveyed to the developing device and collected by rotation of the charge holding member. 2. The toner fall prevention member is configured with an elastic member, and is held in a movable manner selectively in a direction toward and away from the charge retention member in a portion extending toward the cleaning blade. An image forming apparatus according to claim 1, characterized in that: & The image according to claim 2, characterized in that a raised member is provided on a surface of the toner fall prevention member extending toward the cleaning blade and facing the front distribution load holding member. Forming device. 9. The image forming apparatus according to claim 2, wherein the basket front F toner fall prevention member is movably held integrally with the cleaning blade.